Stabilized mixture employing n-(beta-0,0-dialkyldithiophosphoryl) aryl sulfonamides

ABSTRACT

WHEREIN R is selected from the group consisting of phenyl, ptolyl, p-chlorophenyl, 3,4-dichlorophenyl, 2,5-dimethylphenyl mnitrophenyl, and 2,5-dichlorophenyl and (2) a Lewis base and a process for preparing the mixture by dispersing the Lewis base into the sulfonamide.   A mixture comprising (1) a N-(beta-0,0-dialkyldithiophosphoryl)aryl sulfonamides having the formula:

United States Patent 7 Below June6, 1972 [54] STABILIZED MIXTURE EMPLOYING N- (BETA-0,0- DIALKYLDITHIOPHOSPHORYL) ARYL SULFONAMIDES [72] Inventor: John F. Below, Berkeley, Calif.

[73] Assignee: Staufler Chemical Company, New York,

[22] Filed: May 8, 1970 [21] Appl. No.: 37,388

Related US. Application Data [63] Continuation of Ser. No. 644,815, June 9, 1967.

[52] U.S. Cl ..260/944, 71/87, 260/989 [51] ....A0ln 9/36,CO7f9/l6 [58] Field of Search ..260/944, 989

[56] References Cited UNITED STATES PATENTS 3,205,253 9/ 1965 Fancher et al ..260/944 3,275,717 9/1966 Butler... ..260/989 X 3,553,298 1/1971 Hodan .260/989 X Primary Examiner-Joseph Rebold Assistant Examiner-Richard L. Raymond Attorney-Wayne C. Jaeschke and Edwin H. Baker [57] ABSTRACT A mixture comprising (1) a N-(beta-0,0-dia1kyldithiophosphoryl)-aryl sulfonamides having the fonnula:

9 Clairns, Noprawin g s STABILIZED MIXTURE EMPLOYING N-(BETA-0,0- DIALKYLDITHIOPHOSPHORYL) ARYL SULFONAMIDES This application is a streamlined continuation of application Ser. No. 644,815.

This invention relates to a stabilized mixture of certain N- beta-0,0-dialkyldithiophosphoryl)-aryl sulfonamides and a Lewis base and to a process for preparing said mixture.

The N-( beta-0,0-dialkyldithiophosphoryl)-aryl sulfonamides of this invention are those having the formula RSOzNHC HzCHzS P in which R is selected from the group consisting of phenyl, ptolyl, p-chlorophenyl, 3,4-dichlorophenyl, 2,5-dimethylphenyl, m-nitrophenyl, and 2,5-dichlorophenyl. They are known to be useful as selective herbicides, as evidenced by US. Pat. No. 3,205,253.

These sulfonamides are stable upon manufacture, however, they sometimes decompose on storage or during shipping, The exact mechanism of the decomposition is not fully understood, however, it is theorized that heat causes an acid catalyzed rupture of a sulfur-phosphorus of the sulfonamides. It is believed that a fragment of the ruptured molecule which is acidic catalyzes further decomposition of the sulfonamides. Such decomposition has limited the commercial development of these sulfonamides.

It has been found unexpectedly that if a Lewis base is mixed with the sulfonamide, then decomposition is greatly retarded or prevented.

The preferred Lewis bases are organic compounds especially those that are soluble in the sulfonamides of the present invention. A more preferred group is the organic amines such a dipropyl diamine, ethanolamine, and N,N,NN(tetrakis-2- hydroxy-propyl)ethylene diamine.

The most preferred compound is N,N,N',N'(tetrakis-2- hydroxypropyl) ethylene diamine.

Stabilization of the sulfonamides can best be achieved by uniformly dispersing the Lewis base throughout the sulfonamide. Although said dispersing can be achieved in a variety of well-known ways, it is preferred to liquidify the sulfonamide and then to uniformly mix the Lewis base into the sulfonamide by stirring or shaking, for example.

The amount of Lewis base that is dispersed into the sulfonamide is not critical. However, it has been found that from about 0.05 to 1.0 percent by weight stabilizes the'sulfonamides for a sufficient period of time to safely permit nonnal storage, shipping and application of the material.

The stabilization of the N-( beta-0,0-dialkyldithiophosphoryl)-aryl sulfonamides with various Lewis bases is illustrated in the following examples.

EXAMPLE 1 Various Lewis bases of the names and amounts by weight listed in table 1 were mixed with the compound N(beta- 0,0- diisopropyldithiophosphoryl) benzene sulfonamide, called the benzenesulfonamide" hereinafter in the example, by hand shaking. Next to the stabilized mixtures along with an unstabilized amount of the benzenesulfonamide containing no Lewis base were placed in 2 oz. bottles. These bottles were then placed in an oil bath and heated to 100C. for 40 hours. After 40 hours the bottles were removed from the oil bath and the benzene sulfonamides were tested for any chemical degrada tion.

In general such testing involved the separation of the benzenesulfonamide from any degradation products of the benzenesulfonamide by paper chromatography using glutaronitrile as the immobile solvent and isopropyl ether as the mobile. The benzene-sulfonamide was located on the chromatographic paper by spraying the paper with a mixture of brom phenol blue and silver nitrate. The benzenesulfonamide was then analyzed for phosphorus by perchloric acid-nitric acid decomposition and subsequent precipitation and titration of the phosphomolydate precipitate. From this phosphorus analysis the percent degradation of the benzenesulfonamide was calculated.

Specifically the testing was done by marking, small crosses, approximately 1% in. apart, about 1% in. up from the long side of 8% X 8 in. strip of chromatographic paper, Whatman No. 3, MM, parallel with the grain. The paper was then dipped into a 12 percent by volume solution of glutaronitrile in acetone and hung to dry for l to 2 minutes. After the acetone had evaporated, the paper was clamped on a 8 in. square support, and a slow stream of nitrogen gas was directed from glass tubing beneath the paper at the five crosses.

Next 2.0 ml. of CS containing a weighted amount of the benzenesulfonamide, about 30 mg., was distributed on the five marks. The lower 56 in. portion of the paper was then placed in a trough containing isopropyl ether, the trough being situated in the bottom of a 9 X 9 X 3 in. stainless steel chromatographic tank. A glass lid was placed over the top of the tank and the chromatogram was allowed to develop for about 30 minutes.

The chromatogram was removed from the tank and immediately sprayed with a mixture of 5 parts by volume of brom phenol blue (0.5 percent solution of acetone) and 1 part silver nitrate (2.0 percent by volume in acetone). The benzenesulfonamide appeared as bright blue spots against a darker bluegreen background.

The strip of the paper containing the spots was cut from the remainder of the paper and placed in a 250 ml. Erlenmeyer flask. 15 ml. of concentrated HNO and 14 ml. of concentrated HClO, was then added to the flask and the contents were heated swirling until the paper dissolved. Additional NHO was added at the end of the digestion to prevent charring. When the fuming contents of the flask became colorless to pale yellow, heating was discontinued and the flask cooled.

Next the contents were diluted with approximately 50 ml. of water and then neutralized with concentrated Nl-LOH dropwise until the contents turned red. Then 15 ml. of a 60 percent solution of Nl-LNO and 25 ml. of NH MoO solution were added. The Nl-LMoO was prepared by mixing l) a solution made by dissolving 2,400 mi. H O, 1,400 mi. NH OH and 2 pounds M00 with addition of 600 ml. concentrated HNO with (2) a solution of 9,600 ml. H 0 and 4,000 ml. conc. HNO

The flask was then stoppered and agitated for 30 minutes. The resulting precipitate was then separated through a gooch filter using filter pulp as a pad. The precipitate was then washed six times with five 10 ml. portions of H 0. The precipitate and pad were then transferred back to the flask and shaken thoroughly. Finally 10 drops of phenol-phthalein indicator (0.1 percent in ethanol) was added and the solution titrated to the disappearance of pink color with 0.1 N HCl.

The percent degradation of the benzenesulfonamide was calculated by the following equation.

( NE HXNNBOH) (mlnc1XNnc1)-1,732 Sample weight in milligrams Percent degradatlon= Test results of example 1 for N-(beta-0,0-diisopropyldithiophosphoryl) benzensultonamide.

TABLE 1 Percent Y Additive weight Percent degradation None Quinollne- Ethanolamine- Ammonia Dlpropylamlne" Tributylamine N,N,NN' tetrak dlamlne An ablotylamlne"....

H CHgNHz CH3 on CH3 An amino principally of the formula derived from pine resin acids and stabilized.

EXAMPLE 2 Samples of N-(beta-0,0-diisopropyl dithiophosphoryl)-4- methylphenyl sulfonamide, N-( beta-0,0-diisopropyl dithiophosphoryl)-3-nitr0phenyl sulfonamide and N-(beta- 0,0-diethyldithiophosphoryl)-3,4-dichlorophenyl sulfonamide were mixed with 1.0 percent by weight of the abietylamine of example 1. Next these stabilized sulfonamides along with unstabilized samples of them were heated for 40 hours in the manner described in example 1.

The unstabilized N-(beta-0,0-diisopropyl dithiophosphoryl)-4-methylphenyl sulfonamide was found by the chromatographic procedure described in example 1 to have degraded about 92 percent while the stabilized sample of it showed only about 9 percent degradation. The stabilized samples of N- (beta-0,0-diethyl dithiophosphoryl)-3,4-dichlorophenyl sulfonamide and N-(beta-0,0-diisopropyl dithiophosphoryl)-3- nitrophenyl sulfonamide were found to have degraded 72 percent and 48 percent respectively less then the unstabilized samples of them based upon solubility of the materials in carbon disulfide.

lclaim:

l. A stabilized mixture of a compound of the formula RS O2NHCHzCHzS P wherein R is selected from the group consisting of phenyl, ptolyl, P-chlorophenyl, 3,4-dichlorophenyl, 2,5-dimethyl phenyl and m-nitrophenyl; R and R are lower alkyl and an acid neutralizing amount of a Lewis base selected from the group consisting of amines and ammonia.

2. The mixture of claim 1 wherein said Lewis base is an amine.

3. The mixture of claim 1 in which said Lewis base is, N ,N,N,N',(tetrakis-Z-hydroxypropyl) ethylene diamine.

4. The mixture of claim 1 wherein said compound is N- (beta-0,0-diisopropyldithiophosphoryl)-benzenesulfonamide which as the formula 5. The mixture of claim 1 wherein said compound is N- (beta-0,0-diisopropyldithiophosphoryl)-benzenesulfonamide which has the formula S CH and said Lewis base is an amine.

6. The mixture of claim 1 wherein said compound is N- (beta-0,0-diisopropyldithiophosphoryl)-benzenesulfonamide which has the formula S OH;

T I Os omnomoms moan-0H3 and said Lewis base is N,N,N,N',N',( tetrakis-Z-hydroxypropyl) ethylene diamine.

7. The mixture of claim 1 wherein said base is ammonia.

8. A stabilized mixture of a compound of the formula S CH T s omrromcms main-c11 

2. The mixture of claim 1 wherein said Lewis base is an amine.
 3. The mixture of claim 1 in which said Lewis base is, N,N,N'', N'',(tetrakis-2-hydroxypropyl) ethylene diamine.
 4. The mixture of claim 1 wherein said compound is N-(beta-0,0-diisopropyldithiophosphoryl)-benzenesulfonamide which as the formula
 5. The mixture of claim 1 wherein said compound is N-(beta-0,0-diisopropyldithiophosphoryl)-benzenesulfonamide which has the formula
 6. The mixture of claim 1 wherein said compound is N-(beta-0,0-diisopropyldithiophosphoryl)-benzenesulfonamide which has the formula
 7. The mixture of claim 1 wherein said base is ammonia.
 8. A stabilized mixture of a compound of the formula
 9. The mixture of claim 8 wherein said compound is N-(beta-0,0-diisopropyldithiophosphoryl) benzenesulfonamide which has the formula 